It turns out that the British equivalent of the NSA, GCHQ, has been spying on Yahoo webcam users. And they're a bit upset by what their Optic Nerve program revealed. For starters, it turns out that 3-11% of Yahoo! webcam traffic involves "undesirable nudity". [...]

I am still trying to get my head around the implications that the British government's equivalent of the NSA probably holds the world's largest collection of pornographic videos, that the stash is probably contaminated with seriously illegal material, and their own personnel can in principle be charged and convicted of a strict liability offence if they try to do their job. It does, however, suggest to me that the savvy Al Qaida conspirators of the next decade will hold their covert meetings in the nude, on Yahoo! video chat, while furiously masturbating.

There are specific exemptions for members of the security services in the UK laws against porn, including child porn. See for example, Section 1B of the Protection of Children Act 1978 (c. 37):

(1)In proceedings for an offence under section 1(1)(a) of making an indecent photograph or pseudo-photograph of a child, the defendant is not guilty of the offence if he proves that—
..
(c)at the time of the offence charged he was a member of GCHQ, and it was necessary for him to make the photograph or pseudo-photograph for the exercise of any of the functions of GCHQ.